The present invention relates generally to a press-molding process for preparing a powder/fiber compact, and more particularly to a process for manufacturing, with high formability and compactibility, a compacted and cured article from a mixture mass of metal and/or ceramic powders, and/or metal fibers such that the obtained article is given a high degree of strength and subjected to least loss or degradation of properties inherent in such materials.
In the field of manufacturing a compact from such materials as metal powder, fibrous metal and/or ceramic powder (hereinafter referred to as "solid fines" when appropriate), it is considered to press-mold or compact a mass of such solid fines in a mold under pressure in the first step. It was recognized in this field that such method was not capable of attaining a sufficient bonding between the solid fines or powder particles and therefore suffered difficulty in obtaining a compact having a practically sufficient strength.
For the above reason, it has been practiced to apply a sintering process to such compact formed of the solid fines for the purpose of increasing the strength thereof. However, the sintering operation requires a high heating temperature near the melting or fusion point of the materials used and consequently needs high consumption of energy such as electric power, and equipment and procedures for careful control of atmospheres within a furnace. The sintering process has a further shortcoming that the use of extremely high temperatures adversely affects the dimensional accuracy of the obtained products or sintered compacts. Thus, the products are usually subjected to a subsequent step of sizing or any other plastic working in order to rectify the dimensional errors or improve the dimensional accuracy of the end products, especially where they are complicated in configuration. It is still very difficult, however, to improve their dimensional accuracy to the target standard.